function res = fn_int_Tnm(n, m, vx, vf, k)

res = 0;

if n == m
    
    for i = 2:2:(2*n-2)
        
       res = res + 2*fn_int_an(i, vx, vf, k);  
        
    end
    
    res = res + fn_int_an(2*n, vx, vf, k);
    
else
    
    for i = (abs(m-n)+2):2:(m+n-2)
        
        res = res + 2*fn_int_an(i, vx, vf, k);
        
    end
    
    res = res + fn_int_an(abs(m-n), vx, vf, k);
    res = res + fn_int_an(m+n, vx, vf, k);
    
end

end